Background: Recruitment for clinical trials is a major challenge. Movement disorders, which do not have associated diagnostic laboratory tests, may be especially prone to inaccuracy in coding. Our objective was to evaluate the accuracy of diagnostic codes such as cervical dystonia (CD) and PD in an electronic medical record.
Methods: Retrospective chart review was performed to confirm the ICD-9 diagnoses of PD, CD and diabetes mellitus type 2 (DM-2), using published clinical diagnostic criteria (PD, CD) and hemoglobin A1c ≥ 6.5 (DM-2).
Results: 421 charts (n=129, n=142, n=150 for PD, CD and DM-2, respectively) were reviewed. The accuracy rate was different between all diseases examined with an overall p<0.001. In post hoc pairwise comparisons, the accuracy of DM-2 diagnosis by ICD-9 (96.6%) was greater than CD (88.0%) and both greater than PD (55.0%) (p≤0.003).
Conclusions: Using an electronic medical record based screening of clinically diagnosed diseases such as CD may be more accurate than previously thought and may identify potential clinical trial participants even without confirmatory lab tests available.
Keywords: Parkinson disease; clinical research; dystonia.